Session 5 — Weighing the Earth: Gravity, Ice Sheets, and CO₂#
Format A — Paper Autopsy Week 5 Relevance: Climate · Carbon storage monitoring
GRACE satellite gravity · Ice sheet mass loss · CO₂ plume monitoring
Pre-read required
Students receive a 2-page excerpt 48 hours before the session: a paper on GRACE ice mass loss or a gravity-based CO₂ storage monitoring study. Come prepared to discuss the figures.
Hook (0 – 7 min)
Show a GRACE/GRACE-FO monthly gravity anomaly animation over Greenland, 2002–2024 (NASA JPL). No labels. Ask:
“What is changing here and why? What is being measured?”
Pair-share 2 minutes. Take responses before explaining anything.
Discussion (7 – 42 min)
Three organizing questions:
1. The Bouguer correction from lecture was developed for land surveys — how did GRACE change what gravity can do?
2. This paper reports a gravity change of [X] microgals per year over Greenland. Can you estimate what mass change that implies? Try to do an order-of-magnitude calculation. What do you need to assume?
3. What can gravity monitoring tell us about CO₂ plume migration that seismic monitoring can’t — and vice versa? Which would you choose for a carbon storage site and why?
Push hardest on question 3 — there is no single correct answer, and that’s the point.
Relevance
Climate: GRACE/GRACE-FO provides the most direct measurements of Greenland and Antarctic ice sheet mass loss — a primary input to sea level rise projections. The gravity corrections students learned this week are conceptually embedded in the GRACE data processing chain.
Energy: Gravity monitoring is being actively deployed at carbon capture, utilization, and storage (CCUS) sites to track CO₂ density changes over time. SEG 2024 “Geophysics and Sustainability” identifies this as a frontier application.
Go Deeper
NASA GRACE-FO mission overview · SEG 2024 special section “Geophysics and Sustainability”
One name: Dr. Isabella Velicogna, UC Irvine — GRACE ice sheet mass balance. Her group’s code and data are publicly available.